CALCULATION OF
DECLARED DISTANCES
1
The declared distances to be
calculated for each runway direction comprise: the take-off run available
(TORA), take-off distance available (TODA), accelerate-stop distance available
(ASDA), and landing distance available (LDA).
2
Where a runway is not
provided with a stopway or clearway and the threshold is located at the
extremity of the runway, the four declared distances should normally be equal
to the length of the runway, as shown in Figure A-1 (A).
3 Where a runway is provided with a clearway
(CWY), then the TODA will include the length of clearway, as shown in Figure
A-1 (B).
4 Where a runway is provided with a stopway
(SWY), then the ASDA will include the length of stopway, as shown in Figure A-1
(C).
5 Where a runway has a displaced threshold,
then the LDA will be reduced by the distance the threshold is displaced, as
shown in Figure A-1 (D). A displaced threshold affects only the LDA for
approaches made to that threshold; all declared distances for operations in the
reciprocal direction are unaffected.
6 Figures A-1 (B) through A-1 (D) illustrate a
runway provided with a clearway or a stopway or having a displaced threshold.
Where more than one of these features exist, then more than one of the declared
distances will be modified - but the modification will follow the same
principle illustrated. An example showing a situation where all these features
exist is shown in Figure A-1 (E).